Method for the tanning of hides and skins.



GIACOMO DURIO, OF TURIN', ITALY.

METHOD FOR THE TANNING or HIDES AND sKINs.

No Drawing.

To all whom it may concern:

' Be it known that I, GIAcoMo DURIo, a subject of the King of Italy, residing at Turin, Italy, have invented a certain new and useful Improved Method for the Tanning of Hides and Skins, of which the following is a specification.

It is known that the ordinary method of tanning by which hides and skins are submitted to the progressive action of tanning materials, necessitates a considerable length of time, and, consequently, heavy installation expenses, because of the space taken up by the pits, vats, paddles and other similar apparatus. On the other hand, the use of concentrated tanning extracts must always be accompanied in rapid methods of tanning by some mechanical action to keep the hides and skins and the tanning material in motion. This requires costly machinery, as Well as heavy expenses for the motive power and labor, without taking into account the prejudicial action on the hides of this treatment.

The object aimed at in this invention is to eliminate the above inconveniences.

It consists in preparing the pelt in such a way as to favor a natural and rapid ab sorption of the tannin, or, generally, of the tanning material, by eliminating from the pelt all extraneous matters, and by rendering it perfectly neutral, and in a partlcular manner of treating the pelt with tanning extract without the use of leaching pits or other mechanical installations. In the application of this method, after the hides or skins have been prepared by any of the methods in common use, such as by treatment with lime, sodium sulfid, etc., for loosening the hair, and after de-hairing and fleshing, the pre pared pelts are thoroughly cleansed from lime and extraneous matters, which may be done by any of the ordinary methods for deliming skins. They are washed in soft water, and the excess of water is removed by allowing them to lie in pile; or, if desired, they may be pressed. The pelts thus properly prepared, cleansed, dried and in a neutral state, are now in a suitable condition to absorb the tannin without undergoing any mechanical action Whatever, so that after lying in pile, they proceed to the tanning solution. For this purpose pure liquid extracts as put on the market are used,-that is to say, the extracts are used in an undiluted state, for in this state they are in Specification of Letters Patent.

Patented Feb. 29, 1916.

Application filed February 24, 1913. Serial No. 750,271.

the best condition as regards fluidity, etc., and they may be used with or without the addition of any foreign substances.

The hides are piled flat in a vat of proper size; the tails are then folded over upon the heads, and the bottcm hide is then turned out flat and its exposed half painted with a thick layer of extract. The next hide is then turned down on the first-named hide and painted, and so on. When all the hides have been so painted on one half or end, the pile is folded so as to have the heads above the tails, and each head half or end is turned down in turn and painted, the pile finally being left fiat. Obviously, instead of painting the upper side of the hide after having turned down the same, the lower side may be painted when the hide is turned up on the pile. At the end of this treatment, the hides are turned upside down, and their other surfaces are painted in the manner described. Then the hides are left piled flat in the vat. This treatment is repeated at increasing intervals, until the tanning is completed, the excess extract being continuously drawn off as fast as it flows over the hides. The tanning extract is preferably applied by means of long sheepskin brushes, which rapidly absorb the extract.

The vats in which the hide piles are arrange are connected with three series of pipes, each series leading to its individual reservoir. One of said reservoirs contains the fresh extract, and the pipes feeding the same to the vats will be open when the hides are being painted with the extract. The second series of pipes are open at the same time, and these pipes lead to a reservoir in which the excess extract is collected. The pipes of the third series must be closed when the hides are being painted, and are open when the painting is finished, the orifices of the other series being closed; said pipes serve thus to recollect the extract draining off from the hides in the reservoir connected therewith, in which reservoir the extract may be re-concentrated.

It has been determined that complete tannage requires from two to twenty days, according to thickness of the skins or hides. This process, which is based on the immediate absorption of the tannin, or, generally, of the tanning material by the skins prepared in such a way as to facilitate chemical and physical absorption, results in an economy of tanning extract, by taking care used extracts is possible because the chemi-:

cal composition of the extract has not been altered, fermentation and oxidation due to impurities of the hides or skins having been avoided in the tannage.

The tannage proceeds very rapidly and the liquid which is used in excess undergoes no change while that which is used merely loses in concentration without being con- Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

taminated by foreign substances, without fermentation or change. It can thus be concentrated by ordinary means.

What I claim is The process of rapidly tanning hides, which consists in subjecting both surfaces of the hides, after the latter have been washed and freed from all extraneous substances and from the washing water, and while they are'kept stationary in vats, to the action of commercially-pure, undiluted liquid tanning extract; and continuously drawing off the excess extract as fast as it flows over the hides. In testimony whereof I affix my signature in presence of two witnesses.

GIACOMO DURIO.

Witnesses: V

CARLO TORBAR, J OCELYN GOUBEY-RAN.

Washington, D. C. 

